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chore: update pycert_bearssl to detect end entity certificates (#35)

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This commit is contained in:
Noah Laptop 2021-03-31 13:26:12 -07:00
parent 028e33728d
commit 1fe4894800
2 changed files with 23 additions and 4 deletions
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18
tools/pycert_bearssl/cert_util.py
View file

@ -36,6 +36,8 @@ RSA_E_PRE = "TA_RSA_E"
EC_CURVE_PRE = "TA_EC_CURVE"
# EC curve type enum prefix
EC_CURVE_NAME_PRE = "BR_EC_"
# CA flag
CA_FLAG = "BR_X509_TA_CA"
# Template that defines the C header output format.
@ -95,7 +97,7 @@ static const {ray_type} {ray_name}[] = {{
CROOTCA_TEMPLATE = """\
{{
{{ (unsigned char *){ta_dn_name}, sizeof {ta_dn_name} }},
BR_X509_TA_CA,
{ca_flag},
{{
BR_KEYTYPE_RSA,
{{ .rsa = {{
@ -135,7 +137,8 @@ CROOTCA_EC_TEMPLATE = """\
CCERT_DESC_TEMPLATE = """\
* Index: {cert_num}
* Label: {cert_label}
* Subject: {cert_subject}"""
* Subject: {cert_subject}
* Type: {cert_type}"""
def PEM_split(cert_pem):
"""Split a certificate / certificate chain in PEM format into multiple
@ -228,12 +231,17 @@ def decribe_cert_object(cert, cert_num, domain=None):
label = com[b'OU'].decode("utf-8")
elif b'O' in com:
label = com[b'O'].decode("utf-8")
if cert.get_issuer() == cert.get_subject():
cert_type = "Certificate Authority"
else:
cert_type = "End Entity"
# return the formated string
crypto = cert.to_cryptography()
out_str = CCERT_DESC_TEMPLATE.format(
cert_num=cert_num,
cert_label=label,
cert_subject=crypto.subject.rfc4514_string(),
cert_type=cert_type
)
# if domain, then add domain entry
if domain is not None:
@ -279,6 +287,8 @@ def x509_to_header(x509Certs, cert_var, cert_length_var, output_file, keep_dupes
cert_desc.append(decribe_cert_object(cert, cert_index))
else:
cert_desc.append(decribe_cert_object(cert, cert_index, domain=domains[i]))
# detect if the cert is a CA
is_ca = cert.get_issuer() == cert.get_subject()
# build static arrays containing all the keys of the certificate
# start with distinguished name
# get the distinguished name in bytes
@ -307,6 +317,7 @@ def x509_to_header(x509Certs, cert_var, cert_length_var, output_file, keep_dupes
# format the root certificate entry
CAs.append(CROOTCA_TEMPLATE.format(
ta_dn_name=DN_PRE + str(cert_index),
ca_flag=CA_FLAG if is_ca else "0",
rsa_number_name=RSA_N_PRE + str(cert_index),
rsa_exp_name=RSA_E_PRE + str(cert_index)))
elif 'Elliptic' in numbers_typename:
@ -322,6 +333,7 @@ def x509_to_header(x509Certs, cert_var, cert_length_var, output_file, keep_dupes
# and then the exponent
CAs.append(CROOTCA_EC_TEMPLATE.format(
ta_dn_name=DN_PRE + str(cert_index),
ca_flag=CA_FLAG if is_ca else "0",
ec_number_name=EC_CURVE_PRE + str(cert_index),
ec_curve_name=EC_CURVE_NAME_PRE + curve_name
))
@ -344,3 +356,5 @@ def x509_to_header(x509Certs, cert_var, cert_length_var, output_file, keep_dupes
cert_length=str(len(CAs)),
cert_data=cert_data_out,
))
return len(cert_ser)

7
tools/pycert_bearssl/pycert_bearssl.py
View file

@ -136,6 +136,10 @@ def convert(cert_var, cert_length_var, output, use_store, keep_dupes, no_search,
else:
click.echo('Loaded certificate {0}'.format(c.name))
cert_objs.append(cert_parsed)
if no_search and cert_parsed.get_subject() != cert_parsed.get_issuer():
click.echo(f'Warning: certificate {c.name} is an end entity certificate (not a CA). '
'SSLClient may fail to validate if the server certificate changes.')
# find a root certificate for each
root_certs = []
if no_search:
@ -149,7 +153,8 @@ def convert(cert_var, cert_length_var, output, use_store, keep_dupes, no_search,
root_certs.append(cert_dict[cn_hash])
# Combine PEMs and write output header.
try:
cert_util.x509_to_header(root_certs, cert_var, cert_length_var, output, keep_dupes)
written = cert_util.x509_to_header(root_certs, cert_var, cert_length_var, output, keep_dupes)
click.echo(f'Wrote {written} trust anchors to {output.name}')
except Exception as E:
click.echo(f'Recieved error when converting certificate to header: {E}')
exit(1)